Sire De Grugy returned to form in dramatic style as he landed the Betfair Tingle Creek Chase for a second time at Sandown.
Gary Moore's talented two-mile chaser won this race and the Queen Mother Champion Chase in the 2013-14, but since then things had not gone smoothly.
However, he continued the tremendous form of his trainer who was completing a treble after the victories of Flute Bowl and Ar Mad earlier on the card - his third hat-trick from the last three meetings at the track.
A stewards' inquiry was called after Sire De Grugy, a well-backed 100-30 chance, edged out Irish raider Special Tiara by three-quarters of a length, as the first past the post jumped to the left at the last and collided with the runner-up. Vibrato Valtat was third.
Special Tiara, trained by Henry de Bromhead, was the early leader, tracked by Josses Hill and Sire De Grugy before Josses Hill took a crashing fall at the fourth.
Sire De Grugy then took over from Special Tiara at the Railway fences as the pair led from Vibrato Valtat in the build-up to a pulsating climax.
After a tense wait, the placings were confirmed by the stewards and winning rider Jamie Moore said: "It's a lot of credit to the horse, the horse hasn't got a routine any more. He tells us what to do."
Referring to the last-fence incident, he said: "He always jumps left, he's jumped a bit left again at the last, I thought Special Tiara was going to get by me, but he's toughed it out. He went again when Special Tiara got to me. This horse is my best mate."
A disappointed De Bromhead said: "He should have won, obviously he was coming to win the race and the other horse took him out, it was as simple as that.
"I was delighted with his run, and we will decide where we go next when we get home."
Asked if he thought he would have won, Special Tiara's rider Noel Fehily said: "I thought so, at the time I was coming with a real rattle to the last and got turned sideways. That's racing."
